In WebGL, you can load the mip maps manually - whatever the parameter levelis in gl.texImage2D- or you can just load level 0, and then use gl.generateMipmapthem to be generated for you.
mip , gl.texParameteri, gl.TEXTURE_MIN_FILTER of gl.NEAREST_MIPMAP_LINEAR ( ), gl.NEAREST_MIPMAP_NEAREST, gl.LINEAR_MIPMAP_NEAREST gl.LINEAR_MIPMAP_LINEAR.
Mip.
, , gl.generateMipmap(gl.TEXTURE_2D) , , gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST_MIPMAP_LINEAR).